Longitudinal wave
waves in which the displacement of the medium is in the same direction as, or the opposite direction to, the direction of propagation of the wave
A longitudinal wave is a wave in which the particle movement is parallel to the direction of the wave propagation. This means that the particles move left and right which in turn makes the other particles start to oscillate. This creates a wave. Longitudinal waves are also called pressure waves, and sound waves are the most common kinds. As with other waves, the particles do not move with the wave.
